Income Taxes - Schedule of Components of Net Deferred Tax Balances (Details) - USD ($) $ in Thousands	Jan. 31, 2026	Jan. 31, 2025	Jan. 31, 2024	Jan. 31, 2023
Deferred tax assets
Net operating loss carryforwards	$ 482,506	$ 486,505
Accruals and reserves	18,521	16,772
Stock-based compensation	37,114	42,949
Research and development credits	231,718	179,275
Capitalized research and development expenses	295,228	350,729
Other	69,391	54,286
Total deferred tax assets	1,134,478	1,130,516
Less: Valuation allowance	(88,918)	(112,847)	$ (934,816)	$ (1,032,016)
Deferred tax assets, net of valuation allowance	1,045,560	1,017,669
Deferred tax liabilities
Deferred contract acquisition costs	(125,660)	(121,678)
Fixed assets and intangible assets	(65,237)	(54,137)
Other	(40,925)	(21,980)
Total deferred tax liabilities	(231,822)	(197,795)
Net deferred tax assets / (liabilities)	$ 813,738	$ 819,874